It would be nice and probably possible to convert the upstream Java source to JavaScript using automatic methods. I've got a prototype up and running (https://github.com/bjornharrtell/jsts/tree/1.0.0-wip) using java2estree and astring to convert the original source.

Some changes to the original source was needed, recording them here:

1. Removal of circular dependencies involving class hierarchies (i.e Geometry operation methods) (NOTE: can be worked around by monkey patching Geometry as a separate module)
2. Do not use on demand imports (import with * symbol)
3. Rename fields to not have the same name as methods
4. Remove reliance on null argument resolution for overloads (for example the GeometryFactory methods and friends when creating empty geometries)
5. Avoid overloading on methods with more than 3 arguments (addFillet in OffsetSegmentGenerator) (NOTE: should be possible to handle in translation)
6. If overloading inherited method(s), all inherited method signatures must be defined in subclass (CoordinateList, RobustLineIntersector) (NOTE: should be possible to handle in translation)
7. Do not use inner classes (can be replaced with static inner classes + dependency injection)
8. Use alternative to Clonable and/or Object.clone (replace with custom copy impl.)
9. Do not rely on comparison operator for PrecisionModel Type comparisons

First version of modified original source (obsolete, patches in separate branches): https://github.com/bjornharrtell/jts-topo-suite/tree/no_circular_deps

java2estree: https://github.com/bjornharrtell/java2estree

I was able to find the javadocs for jts, but they are incredibly hard to read in terms of learning how to use that library. Seems more like a handy reference for someone that already knows how to use that library.

I scoured the jts github repo but I don't see any links to places that show some examples or how to actually use this very capable but complicated API.

Do you happen to know where one might find this?

I've just been checking out JSTS - great stuff! In addition to the current JSTS browser environment it would also be really useful to have it packaged up and available as a Node.js module via NPM.

Building on latest Angular (12.x) which uses Webpack 5 under the hood, TypeScript 4.2.4.

JSTS usage is: import * as jsts from 'jsts';

and then inside a local method: const reader = new jsts.io.GeoJSONReader();

also using @types/jsts: "^0.17.5" for typings

Should I be using a more specific import scheme?

Will try to provide a more reproducible example if this is not enough detail.

Hi there,

I've been trying to access the PointLocator class to run a point in polygon test.

Using the built version

const jsts = require('jsts')
const PL = new jsts.algorithm.PointLocator()

I get TypeError: jsts.algorithm.PointLocator is not a constructor

I also had a go at building something based on the ES6 modules

import PointLocator from 'jsts/src/org/locationtech/jts/algorithm/PointLocator'

export function jsts (point, poly) {
    const pe = new PointLocator()
    return pe.intersects(point, poly);
}

However when I do that I get the wrong result for a simple case...

Am I missing anything obvious?

Thanks, Rowan

In our project https://github.com/geops/openlayer-editor, we use jsts as es6 import and after compilation we have this issue in the browser console:

Uncaught SyntaxError: Identifier 't' has already been declared

2 generated variables by the compiler have the same name . It seems it' caused by some dead code in DirectedEdgeStar.js, Removing it fix our issue.

As of version 1.5.0, only some of the JTS public classes are exported in the ready-to-use ES5 build. Nevertheless, it seems that all classes and their implementations are part of the file, so you likely don't save a lot of bytes by just not exporting many of the classes. We actually require some classes from noding, in order to sanitize user-drawn polygons; only three are publicly available. We need others as well.

What are the reasons behind that? Shouldn't the default build of a topology library expose all its features by default, as JTS does in Java? Since java.util.Collection based classes are used as input types for some of the algorithms (e.g. FastNodingValidator), for my mind, most/many of the Java classes should be exported as well.

Quoting part of your answer from #321

The current exports are simply a set of the most common functions that also are all covered by tests.

What are the most common functions? I reckon this is hard to tell, since this always depends on the project, JSTS is used in. Also, it's quite awkward to export features on demand (for you and for those, asking for features). My personal rule of thumb for this library is to expose everything, that is also publicly available in the Java version. So, people can easily test all available features and functions, without bothering with a (more or less) complex build system.

Of course, people could create their own builds. However, I'd like to turn this around. If someone feels that the full library is too big in size and contains too much unused stuff, he's welcome to build his own version.

Maybe I'm missing something, but it seems that whatever you throw at it, isSimple(); always returns true for Simple Feature Spec validation. From Wikipedia: "In general, a 2D geometry is simple if it contains no self-intersection."

Yet, with some testing, self-intersecting polygons can be shown to be false for the validation isValid(); but at the same time true for isSimple();

See gist for the test script. It looks straightforward enough to me but maybe I'm missing something.

Thanks in advance!

Hi,

I want to report a bug in the [email protected]. I got it when my code was trying to check if a two GeometryCollections had any intersections.

This is the error from browser console:

monkey.js:39 Uncaught ReferenceError: MapOp is not defined
    at Nt.H.intersection (monkey.js:39)
    at demo ((index):62)
    at window.onload ((index):129)

This bug is from this place.

I saw that MapOp is not anywhere defined in the repository so I made a decision about added function MapOp() {} into my code just like you have here in [email protected].

Here is my code to reproduce this bug. If you want to see if my solution works then you have to uncomment a script statement from HTML file.

I am using jsts as part of Create-React-App together with OpenLayers. Works so far following the hints at #323 (that is, using static functions like with import BufferOp from 'jsts/org/locationtech/jts/operation/buffer/BufferOp';.

This works in development mode, but when I run the production build step it fails:

$ yarn run build
yarn run v1.6.0
$ react-scripts build
Creating an optimized production build...
Failed to compile.

Failed to minify the code from this file:

        ./node_modules/jsts/extend.js:2

Read more here: http://bit.ly/2tRViJ9

error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
ERROR: "build-js" exited with 1.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

1. The given link http://bit.ly/2tRViJ9 hints at the point that jsts is wrongly published to npmjs. There are some issues regarding ES6 modules / webpack that say that something is broken, e.g. #311. I am not sure how to go forward here.
2. Well, actually, it does not even work in IE11 when in development mode. Error is syntax error:

/***/ "./node_modules/jsts/java/lang/Character.js":
/*!**************************************************!*\
  !*** ./node_modules/jsts/java/lang/Character.js ***!
  \**************************************************/
/*! exports provided: default */
/*! exports used: default */
/***/ (function(module, __webpack_exports__, __webpack_require__) {

"use strict";
/* harmony export (immutable) */ __webpack_exports__["a"] = Character;
function Character () {}
Character.isWhitespace = c => ((c <= 32 && c >= 0) || c == 127)

This is a arrow function. Not sure why it is like this although webpack together with babel is used.

Problems only exist when using jsts package. I have a dozen of other dependencies where it works.

core.js:1448 ERROR TypeError: Ht.toLineString is not a function at Wi.getErrorMessage (jsts.min.js:18) at Wi.checkValid (jsts.min.js:18) at ji.checkValid (jsts.min.js:18) at Function.ji.checkValid (jsts.min.js:18) at Ji.computeOverlay (jsts.min.js:18) at Ji.getResultGeometry (jsts.min.js:18) at Function.Ji.overlayOp (jsts.min.js:18) at Sr.getResultGeometry (jsts.min.js:19) at Function.Sr.overlayOp (jsts.min.js:19) at bt.union (jsts.min.js:9)

JSTS is currently based on JTS 1.17.x. Since then there has been two feature releases of JTS, 1.18 and 1.19.

It's unfortunately a non trivial effort to update because the new things coded in JTS uses features of Java that my transpiler (https://github.com/bjornharrtell/java2estree) currently cannot handle.

I also carry several patches on JTS 1.17.x to make it work currently which further complicates this.

Each of the 3 Subclasses of BasicPreparedGeometry throw an Error if you call the constructor.

TypeError: Cannot read properties of undefined (reading 'apply') at Function.getCoordinates (node_modules/jsts/org/locationtech/jts/geom/util/ComponentCoordinateExtracter.js:16:10) at PreparedPolygon.apply (node_modules/jsts/org/locationtech/jts/geom/prep/BasicPreparedGeometry.js:13:60) at new BasicPreparedGeometry (node_modules/jsts/org/locationtech/jts/geom/prep/BasicPreparedGeometry.js:6:40) at new PreparedPolygon (node_modules/jsts/org/locationtech/jts/geom/prep/PreparedPolygon.js:13:5)

Testcase

it(' Fail PreparedPolygon' ,() => {
const gf = new GeometryFactory()
const reader = new WKTReader(gf)
const poly = reader.read('POLYGON((0 0, 1 0, 1 1, 0 1, 0 0))')
PreparedGeometryFactory.prepare(geom)
}

If you put a LineString or a Point in it, it fails as well.

To fix it simply call the super constructor with the given geometry.

PreparedPolygon:

constructor() {
    super(arguments[0])
    PreparedPolygon.constructor_.apply(this, arguments)
}

Proposal to fix #285. Sadly, tsc fails because of private classes which are (implicitly?) imported. Execute npm run ts-declarations (I didn't use Yarn) to show the error messages.

You can change --outFile dist/index.d.ts to --outDir dist/types to generate .d.ts files for each JavaScript file.

Hello!

I am looking for a concave hull function, which is part of the original jts implementation: https://github.com/locationtech/jts/blob/master/modules/lab/src/main/java/org/locationtech/jts/hull/ConcaveHull.java

What is required to port and expose the ConcaveHull.java class via jsts?

Many thanks for this great library! :)

Hello, I caught the lack of implementation of the method in a large number of newer versions of JSTS

Version bug: 1.5.0 - 2.5.0

in version 1.4.0 there is: RelateOp.disjoint = function (g1, g2) { return !g1.intersects(g2); }; in newer versions there is no this entry (RelateOp.js 2.5.0)

so the entry (monkey.js): Geometry.prototype.disjoint = function(g) { return RelateOp.disjoint(this, g) } does not make sense

I even found a security for it in: BasicPreparedGeometry.js